Backlight is a separate device located behind a liquid crystal display panel, used to provide a surface light source for the liquid crystal panel. Therefore, lighting performance of a backlight will directly affect the display quality of a liquid crystal display device.
Backlight is mainly comprised of lighting tubes, a light guide plate and a reflecting component, etc, wherein the reflecting component provided on the lower surface of and the light guide plate are used to reflect light traveling toward the lower surface, within the light guide plate. An existing reflecting component is mainly composed of a first protective layer, a reflective layer and a second reflective layer, which are sequentially laminated. The upper surface of the first protective layer is located close to the lower surface of the light guide plate. The first and second protective layer is mainly used to protect and support the reflecting component. Specifically, the first and second protective layers can be made from PET (polyethylene terephthalate), or other polyester material.
During manufacturing a backlight, some foreign bodies undetectable by the naked eye, with a dimension less than 20 micrometers, will fall into the gap between the first protective layer and the light guide plate Since both the first protective layer and the light guide plate have smooth surfaces, when the backlight undergoes vibration, the foreign bodies existing between the first protective layer and the light guide plate will cause friction with the first protective layer and the light guide plate. As a result, the first protective layer and the light guide plate are scratched by the foreign bodies, producing undesirable scratches in the backlight, and bright line scratches or dot scratches on displayed images.
To avoid those undesirable scratches caused by the foreign bodies in the backlight, a existing design is proposed, wherein tiny and soft protrusions are provided on the contact surface between the upper surface of the first protective layer and the lower surface of the light guide plate, so as to reduce the contact area between the upper surface of the first protection layer and the lower surface of the light guide plate, hence reducing the areas of the first protective layer and the light guide plate to be scratched by the foreign bodies.
However, because those protrusions tend to fall off under lager friction, and become foreign bodies between the first protective layer and the light guide plate, hence unexpectedly increasing the risk of scratches between the first protective layer and the light guide plate, as well as the risk of scratches on the backlight.